Space agencies and companies work on the program of sending into the orbit autonomous servicing satellites, which could repair damaged commercial satellites. In October 2011 Space Mechatronics and Robotics Laboratory started the project "Design and construction of a prototype of the manipulator as a key component of the satellite orbit servicing system" implemented under the LEADER II program of National Centre for Research and Development. LEMUR, the name of the project was chosen by voting of the project team members.

A robotic system designed to operate in space environment is usually very complex, although it comprises the same elements as robots that work for us on Earth, i.e. links and kinematic joints. A novel concept of the joint employed in LEMUR manipulator is based on the direct drive motor and cycloidal gear. In our project we have focused on optimizing the joint design for space application, specifically on minimizing the mass and reducing backlash effects of the cycloidal gear as well as on maximizing the joint (direct drive and cycloidal gear) efficiency. The optimization was performed in a series of simulations that used FEM software and was finally tested on a few prototypes.

Assembled model of the joint at left. One stage epicycloid gear at right.